James salter farmer



No. 394,164. Patented Dec. 11, 1888.

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N. PETERS. Five UNITED STATES PATENT ()FFICE.

JAMES SALTER FARMER, OF SALFORD, COUNTY OF LANCAS ER, ENGLAND.

ELECTRIC CONTACT-MAKER.

SPECIFICATION forming part of Letters Patent No. 394,164, dated December 11, 1888. Application filed August 27, 1888. Serial No. 283,876. (No model.)

To all whom it may concern.-

Be it kn own that 1, JAMES SALTER FARMER, a subject of the Queen of Great Britaim'residing at Saltord, in the county of Lancaster, England, have invented an Electric Contact- Maker, of which the following is a specification.

My invention consists, mainly, in the construction and arrangement of an electric contact-maker which is particularly applicable for use in conjunction with apparatus to be employed at telephonic call-ot'tlces, or else where, when advantageous or desirable.

In constructing an electric contact-maker according to my invention I employ two hollow vessels, which are made of glass or other electrical non-conductor, and are preferably pear-shaped in form. The necks of these two vessels are united by a metal collar made in two pieces insulated from one another by suitable insulating material, but with a central hole forming a passage between the two vessels. Each portion of the metal collar has an arm formed with it, and these two arms act as pivots upon which the contact-maker, which resembles an ordinary hour-glass, is supported and is free to turn. Each of the two linewires for the electric circuit is connected, one to each arm of the contact-maker, within which are placed a number of very small copper pellets or other metal, or other suitable material or liquid, preferably of high electrical conductivity. I propose to exhaust the air from the two glass bulbs, so as to form a vacuum within the contact-maker.

In order that my invention may be fully understood and readilycarried into effect, I will describe the accompanying sheet of drawings, reference being had to the figures and letters marked thereon.

Figure l is a sectional elevation taken on the line A B, Fig. '2, and Fig. 2 is an end view of an electric contact-maker made according to my invention. Fig. 3 is a sectional plan of a central part of the apparatus taken on the line C D, Fig. 1, and Fig. *1: is a side view of the same part.

In the views, a a are the two glass vacuumbulbs, which contain the mercury or other electrical conductor. The neck of each bulb is fitted and cemented or otherwise secured in a recess in the metal collar 6, which is made in two parts divided by a piece of lignumvitae, c, or other suitable insulating substance, the two parts being held together by collars (Z d, and the piece c being cut away centrally to leave a central passage in the metal between the two bulbs (I (z, the passage being contracted in the center, as shown in Fig. 1, so as to check the too rapid flow of the mercury.

Each portion of the collar 1) is formed with an arm, I), and these arms are fitted in bearings c, which rest upon insulalingpcdestals g, to which the bearings e are secured, the pedestals being bolted to a plate, 1. The cir cuit-wires h are secured, one in each bearing e, by the screws 1', and a screw, j, is shown to hold the collar Z) and the bulbs u a in the desired position while the mercury or other cond uctor is passing from one bulb to the other; but a spiral spring, or any other suitable device, may be employed for the purpose.

The action of the contact-maker is as follows: \Vhen the two glass bulbs (l u are in a vertical position, with all the mercury, metal pellets, or equivalent conducting material in the lower bulb, the electric circuit will be broken; but by turning the contact-maker on its pivots b I) and reversing the position of the two bulbs the mercury, metal pellets, or equivalent will flow slowly from the upper bulb through the central passage into the lower bulb, thereby completing the electric circuit as they touch the two portions of the metal collar 1) until all the mercury, metal pellets, or equivalent have passed into the lower bulb.

The contact-maker is particularly adapted for use in telephonic call-offices and other places where the public, by payment of a prescribed fee, are entitled to the use of the telephone or other electric apparatus for a certain specified time.

The time allowed for the use of the instrum ent regulates the quantity of mercury, metal pellets, or equivalent conducting material employed to complete the electric circuit.

\Yhatl claim as my invention, and desire to secure by Letters Patent of the United States, is

An electric contactmaker consisting of two vesselssuch as the bulbs a u1nounted on an axle and containing a mobile electrical conductor, the metal collar made in two pieces, I) b, insulated but not wholly covered by the piece 0, a channel connecting the vessels, each piece I) being in electrical communication with one of the circuit-wires, and the whole being so arranged that when the mobile conductor is in the lower vessel and the position of the two vessels is reversed the flow of the said conducting material from the upper into the lower vessel completes the electric circuit, substantially as and for the purposes herein described, and as illustrated by the drawings annexed.

In witness whereof I have hereunto set my hand in presence of two witnesses.

JAMES SALTER FARMER.

\Vitnesses:

H. B. BARLow, HERBT. ROWLAND ABBEY, Both of 17 St. Anns Square, llfa'nchesze'r,

England. 

